Many types of medical diagnostic and therapeutic systems comprise one or more probes, which contact the patient's body, and a control console, which receives signals and, in some cases, controls the functions of the probes. For example, cardiac catheters that are used for invasive diagnosis and treatment are typically configured in this way. In systems known in the art, such catheters are generally connected to the control console by a wired analog interface. Newer catheters, however, may communicate with the console via a wireless interface.
For example, U.S. Pat. No. 6,266,551, whose disclosure is incorporated herein by reference, describes, inter alia, a wireless catheter, which is not physically connected to signal processing and/or computing apparatus. Rather, a transmitter/receiver is attached to the proximal end of the catheter. The transmitter/receiver communicates with signal processing and/or computer apparatus using wireless communication methods, such as IR (infra red), RF (radio frequency) or acoustic transmissions. One benefit of this type of configuration is that the catheter, which is inserted into the (electrically sensitive) heart can easily be made electrically floating. Another benefit is a reduction in the amount of cabling and wiring in which an operator might get entangled and/or accidentally pull out of the body. Still another advantage is the ease of sterilizing and maintaining the sterility of such a catheter, since the entire catheter may be sterilized as a single unit.
Another example of a wireless medical sensing device is a wireless ECG patch, developed by IMEC (Leuven, Belgium). The core of the wireless ECG patch consists of a miniaturized wireless sensor node integrated on a flexible substrate. It includes a commercial microprocessor enabling local digital signal processing, a 2.4 GHz radio link and a miniaturized rechargeable battery. In addition, the sensor node features a fork-antenna and a snap-on connector (for connection to an electrode). The wireless ECG patch can work in continuous monitoring mode, in which ECG- or EMG-data is continuously transmitted to a receiver, at a sample frequency between 250 and 1000 Hz. Further details of this device are described on the IMEC.be Web site.